package com.reggie.filter;

import cn.hutool.core.util.ObjectUtil;
import cn.hutool.json.JSONUtil;
import com.reggie.common.BaseContext;
import com.reggie.common.R;
import com.reggie.util.PatchMatchUtil;
import lombok.extern.slf4j.Slf4j;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * 登陆检查
 */
@Slf4j
@WebFilter(filterName = "LoginCheckFilter", urlPatterns = "/*")
public class LoginCheckFilter implements Filter {
    /**
     * Called by the web container to indicate to a filter that it is being
     * placed into service. The servlet container calls the init method exactly
     * once after instantiating the filter. The init method must complete
     * successfully before the filter is asked to do any filtering work.
     * <p>
     * The web container cannot place the filter into service if the init method
     * either:
     * <ul>
     * <li>Throws a ServletException</li>
     * <li>Does not return within a time period defined by the web
     *     container</li>
     * </ul>
     * The default implementation is a NO-OP.
     *
     * @param filterConfig The configuration information associated with the
     *                     filter instance being initialised
     * @throws ServletException if the initialisation fails
     */
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        Filter.super.init(filterConfig);
    }

    /**
     * The <code>doFilter</code> method of the Filter is called by the container
     * each time a request/response pair is passed through the chain due to a
     * client request for a resource at the end of the chain. The FilterChain
     * passed in to this method allows the Filter to pass on the request and
     * response to the next entity in the chain.
     * <p>
     * A typical implementation of this method would follow the following
     * pattern:- <br>
     * 1. Examine the request<br>
     * 2. Optionally wrap the request object with a custom implementation to
     * filter content or headers for input filtering <br>
     * 3. Optionally wrap the response object with a custom implementation to
     * filter content or headers for output filtering <br>
     * 4. a) <strong>Either</strong> invoke the next entity in the chain using
     * the FilterChain object (<code>chain.doFilter()</code>), <br>
     * 4. b) <strong>or</strong> not pass on the request/response pair to the
     * next entity in the filter chain to block the request processing<br>
     * 5. Directly set headers on the response after invocation of the next
     * entity in the filter chain.
     *
     * @param request  The request to process
     * @param response The response associated with the request
     * @param chain    Provides access to the next filter in the chain for this
     *                 filter to pass the request and response to for further
     *                 processing
     * @throws IOException      if an I/O error occurs during this filter's
     *                          processing of the request
     * @throws ServletException if the processing fails for any other reason
     */
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        log.info("当前线程ID：{}", Thread.currentThread().getId());
        HttpServletRequest servletRequest = (HttpServletRequest) request;
        HttpServletResponse servletResponse = (HttpServletResponse) response;
        log.info("登陆检查过滤：{}", servletRequest.getRequestURI());
        // 获取URI
        String requestURI = servletRequest.getRequestURI();
        // 定义放行处理URI数组/列表
        String uri[] = {
                "/employee/login",
                "/employee/logout",
                "/backend/**",
                "/front/**",
                "/user/sendMsg",
                "/user/login"
        };
        boolean check = PatchMatchUtil.check(uri, requestURI);
        // 不需要处理
        if (check) {
            log.info("放行：{}", requestURI);
            chain.doFilter(servletRequest, servletResponse);
            return;
        }
        // 需要处理
        // 处理后台管理登录
        if (ObjectUtil.isNotNull(servletRequest.getSession().getAttribute("employee"))) {
            log.info("后台管理登录用户：{}", servletRequest.getSession().getAttribute("employee"));
            Long employeeId = (Long) servletRequest.getSession().getAttribute("employee");
            BaseContext.setCurrentUserId(employeeId);
            chain.doFilter(servletRequest, servletResponse);
            return;
        }
        // 处理前台用户登录
        if (ObjectUtil.isNotNull(servletRequest.getSession().getAttribute("user"))) {
            log.info("前台外卖登录用户：{}", servletRequest.getSession().getAttribute("user"));
            Long userId = (Long) servletRequest.getSession().getAttribute("user");
            BaseContext.setCurrentUserId(userId);
            chain.doFilter(servletRequest, servletResponse);
            return;
        }
        // 未登录
        log.info("未登录");
        servletResponse.getWriter().write(JSONUtil.toJsonPrettyStr(R.error("NOTLOGIN")));
    }

    /**
     * Called by the web container to indicate to a filter that it is being
     * taken out of service. This method is only called once all threads within
     * the filter's doFilter method have exited or after a timeout period has
     * passed. After the web container calls this method, it will not call the
     * doFilter method again on this instance of the filter. <br>
     * <br>
     * <p>
     * This method gives the filter an opportunity to clean up any resources
     * that are being held (for example, memory, file handles, threads) and make
     * sure that any persistent state is synchronized with the filter's current
     * state in memory.
     * <p>
     * The default implementation is a NO-OP.
     */
    @Override
    public void destroy() {
        Filter.super.destroy();
    }
}
